Researchers at the University of Southern California (USC) Viterbi School of Engineering have developed a biocompatible and biodegradable alternative to conventional plastic by incorporating a mineral found in seashells. The innovation aims to combat ocean plastic pollution while offering designers and manufacturers a safer, circular material for use in disposable products and beyond.

Marine-Safe Materials Inspired by Nature
Plastic makes up around 80% of marine pollution, with an estimated 8–10 million metric tons entering oceans each year. In response, the USC team led by Dr. Eun Ji Chung, a biomaterials expert, created a prototype material that could offer a sustainable solution. Their new composite combines amorphous calcium carbonate (ACC)—commonly found in seashells—with poly(1,8-octanediol-co-citrate) (POC), a citric acid-based biodegradable polymer already used in medical applications such as orthopedic fixation devices.

The resulting material, known as POC-CC, is a strong, flexible plastic substitute designed to break down in marine environments without leaving behind harmful microplastics.

Plastic Alternative with Biodegradability and Strength
Dr. Chung was inspired to tackle the issue of plastic waste during the COVID-19 pandemic, where she observed the overwhelming use of disposable lab and medical materials. Revisiting her early work in biodegradable polymers, she hypothesised that calcium carbonate from seashells, like hydroxyapatite from bone, could strengthen and stabilise biopolymers for broader use.

By heating and curing the mixture of POC and calcium carbonate, the team produced a plastic-like material robust enough to be shaped into soda can holder rings. This prototype application demonstrates the material’s viability for industrial-strength single-use items that can degrade naturally in seawater.

Tested in Ocean-Like Conditions
To evaluate the material’s performance, the researchers incubated POC-CC in simulated seawater for six months. They observed that degradation rates increased with higher concentrations of POC, while the addition of calcium carbonate helped maintain the ocean water’s pH. To test marine safety, the material was incubated alongside green algae (Scenedesmus sp.), with high cell viability confirming its biocompatibility with marine microorganisms.

These findings confirmed that POC-CC is not only biodegradable but also safe for marine life, presenting a promising alternative to petroleum-based plastics that persist in aquatic ecosystems.

Application Potential for Designers
For designers exploring sustainable materials, POC-CC offers a wealth of possibilities. It can be used to create biodegradable straws that are stronger than paper and safer than metal alternatives. It is suitable for eco-conscious packaging solutions and disposable items like trays and beverage rings. Looking ahead, it may also find use in biomedical devices and even temporary interior elements where short-term performance and biodegradability are desirable.

Currently, the team is developing a second-generation version of the material with an accelerated degradation rate to support commercial scalability.

Source: USC
Photo: Camera-man